If \(X\)  is a topological space then we let \(\mathcal {B}(X)\)  denote the Borel \(\sigma \) -algebra on \(X\) , we let \(\mathcal {M}(X)\)  denote the set of signed Radon measures on \((X,\mathcal {B}(X))\) , and we let \(\mathcal {P}(X)\subset \mathcal {M}(X)\)  denote the set of all probability measures on \((X, \mathcal {B}(X))\) , i.e. all \(0\leqslant \mu \in \mathcal {M}(X)\)  with \(\mu (X)=1\)  (see e.g. [1]}, [2]}, [3]}). For \(k\in \mathbb {N}\)  and a multiindex \(\alpha \in \lbrace 0,1\rbrace ^k\)  we write \(|\alpha |=\alpha _1+\dots +\alpha _k\)  and \(\bar{\alpha } = \mathbb {1}-\alpha =(1-\alpha _1,\dots ,1-\alpha _k)\) , and we let \(x_{\alpha }\)  be the vector of length \(|\alpha |\)  consisting of the elements \(x_i\)  of \(x\)  for which \(\alpha _i\)  is non-zero. For a vector \(x=(x_1,\dots ,x_k)\)  we write \(\widehat{x}_i = (x_1,\dots ,x_{i-1},x_{i+1},\dots ,x_k)\) . For a vector \(\xi =(\xi _1,\dots ,\xi _k)\)  we write \(|\xi ^\alpha | = |\xi _1|^{\alpha _1}\cdots |\xi _k|^{\alpha _k}\)  with the convention \(0^0=1\) .
